The process of rebuilding a Nikki carburetor includes finding a proper rebuild kit, removing the carburetor from the engine, separating and replacing parts, cleaning and reassembling, as stated by eBay. The rebuild kit, also known as a carb overhaul kit, consists of all the replacement parts typically switched out on a particular carb during a rebuild.
To remove the carburetor safely from the engine, first disconnect the spark plug lead and tape it off so that it cannot touch the spark plug. Remove the air cleaner assembly and turn off the fuel valve at the bottom of the fuel tank. Finally, remove the mounting bolts from the Nikki carb and slip it out of the engine. Work in an area with plenty of counter or table space while removing parts.
Replace mixture screws with bends or signs of damage. Larger, metal components and plastic parts need to go in a cleaning mixture to soak. Use an all-purpose part cleaner and leave the carb parts to soak in a large tub for about a 15 minutes. Use a small wire brush and carb cleaner to remove any debris and grit on any part. Once the parts are clean and dry, begin the reassembly process. Use photos and product manuals as a reference. Swap in the new parts from the carburetor rebuild kit throughout the reassembly process.